I wish to build a gate across a 3.8m wide driveway.

There is a concrete column on one side which I can fix the hinges to (a post into the ground is not an option) and a brick wall on the other side which I can fix the latch to.

For aesthetic reasons I want to use timber. How should I construct the gate for strength? I imagine it will need diagonal bracing to prevent it from sagging at the end furthest from the hinges. Are there any other things I should do? What size of lumber should I use? Any resources I can use as a guide?

  • How tall should the gate be?
    – Tester101
    Oct 17, 2012 at 11:07
  • Tall enough to prevent opportunistic climbers, I guess. If someone has a ladder I'm not expecting to stop them, but I don't want anyone vaulting over it. So I guess perhaps 2m?
    – jbg
    Oct 17, 2012 at 20:25
  • Well, how tall are the concrete column and/or brick wall? You'll want your gate <= to the height of the supporting members, otherwise it will look odd.
    – Tester101
    Oct 17, 2012 at 23:36
  • The concrete column is about five metres tall and the brick wall about three metres, so that shouldn't be an issue.
    – jbg
    Oct 18, 2012 at 0:58
  • What type of gate would you like to make, a sliding gate or a swinging gate? If you build a swing gate, are you opposed to splitting it in the middle?
    – Tester101
    Oct 18, 2012 at 11:02

2 Answers 2


In an attempt to answer some of the questions raised in your posting let me respond in answer format.

1) It can be advantageous in some situations to affix a timber post to the brick or concrete posts/walls in either side of the gate opening. This post can then serve as a better medium into which to attach hinges and latches.

2) A 3.8 meter wide gate will develop a huge amount of lever arm out at the latch end of the gate and this needs to be taken into account when developing the gate design.

3) The size of wood used can play a big part in how heavy the gate will end up being. The type of wood can play a role as well. This is one reason that boards are often used for gate facing instead of thicker planks. Cedar wood is also much lighter than hard wood like oak and thus becomes a popular choice for gates.

4) Adding appropriate bracing into the design of the gate will keep the gate from sagging.

5) Successful wide gates can often benefit from making the aforementioned side posts much higher than the gate opening and then using a cable from the top down to the end of the gate away from the hinges to help support the weight of the gate. Sometimes you can see the tops of the two higher posts connected across by a horizontal member. This provides support from post to post to keep the weight of the gates from pulling the posts to the sides.

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I built a gate about 14 ft (4.2m) across. I'm an amateur so I can't really tell you the right way to do it, but there are a few issues I found with building a really wide gate:

  • The entire gate twists if you put pressure on it from the top or bottom corner, so it might be better if you made two gates that meet in the middle.
  • The outer edge of the gate sags, even with a diagonal support, so I had to add a wheel with a spring to provide more support.

Make sure you position the diagonal brace so that it runs from the top of the outer edge to the bottom of the inner edge. This will provide the proper support since the inner edge is supported well by the hinge.

  • I would recommend to clarify "inner" and "outer" edge. It would be better to say that the diagonal brace should start at the bottom of the gate at the hinge side and rise toward the top of the gate at the latch side.
    – Michael Karas
    Oct 17, 2012 at 12:44

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